The News Journal reports that the National Oceanic and Atmospheric Administration Marine Fisheries declared it an "unusual mortality event," which is called when higher-than-normal numbers of marine mammals die for unknown reasons. An agency spokeswoman said details will be provided Thursday.

Marine Education, Research and Rehabilitation Institute Executive Director Suzanne Thurman said a decomposing whale washed into shallow water in the Delaware Bay recently, but the weather is hampering efforts to study it. Thurman said it apparently was a juvenile humpback. If confirmed, it would be the fourth stranded in Delaware waters in a year, an unusually high number.

Four have stranded off Virginia and there was a stranding last fall off Long Island.